the sucker king Posted December 11, 2011 Share Posted December 11, 2011 A few years back I found a 91 turbo legacy in the junkyard with only 60k on the odometer. I looked under the rear end, the vlsd was still there but missing a stub axel. I opened the trunk, and low and behold it was there. I don't know if somebody removed it so others wouldn't take the diff before they could get to it or what, but I took the diff and the stub. Now it's years later, and I want to use it. Here is a pic of the stub: It has a ring clip on the diff side, visable in the pic. How do you put this back together, am I missing anything, etc? Years ago I downloaded an exploded view of a VLSD but since lost the file. anyone? ................. Link to comment Share on other sites More sharing options...
Crazyeights Posted December 11, 2011 Share Posted December 11, 2011 It should just push in and lock. You might have to give it a few taps to get the snap ring to lock. Looks like the same setup used on MANY FWD axles. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 11, 2011 Share Posted December 11, 2011 Just tap it in till it snaps into place. No tricks here. GD Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 11, 2011 Share Posted December 11, 2011 you might go ahead and get 2 new seals, pop out the other side and swap sides on reassembly - just to distribute the wear. cool find! Link to comment Share on other sites More sharing options...
bork Posted December 11, 2011 Share Posted December 11, 2011 Can someone translate please, I'm trying to learn.What is it & do? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 11, 2011 Share Posted December 11, 2011 Can someone translate please, I'm trying to learn.What is it & do? look about halfway down here;http://www.iwsti.com/forums/how-install/116053-how-change-rear-axle.html Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 look about halfway down here;http://www.iwsti.com/forums/how-install/116053-how-change-rear-axle.html Why does the ring clip stay in the diff in the pics in the link and in my pic it stayed on the stub? bork- VLSD stand for viscous limited slip differential. The nifty thing about a vlsd is where a normal rear differential will supply power to whichever wheel offers the least resistance (ie the wheel that spins on ice), the vlsd transfers the power "from the wheel that slips to the wheel that grips". Link to comment Share on other sites More sharing options...
bheinen74 Posted December 12, 2011 Share Posted December 12, 2011 It is a reverse snap ring. It is designed to have a little movement smaller to the axle stub shaft when you pop it into the carrier. Think of it this way, Think just a regular snap ring that you spread and put over a shaft. This one, the snap ring compresses smaller while it is inserted into the diff carrier, then it spreads back once in place at that lock it in. It has outward pressure .... Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 It is a reverse snap ring. It is designed to have a little movement smaller to the axle stub shaft when you pop it into the carrier. Think of it this way, Think just a regular snap ring that you spread and put over a shaft. This one, the snap ring compresses smaller while it is inserted into the diff carrier, then it spreads back once in place at that lock it in. It has outward pressure .... I asked why would it be left in the diff in one circumstance and on the stub in another. Link to comment Share on other sites More sharing options...
bheinen74 Posted December 12, 2011 Share Posted December 12, 2011 I have read, and re-read, and reread again the first post for your question, and did not see that part.. Actually the post more was like i found this, and now what? not asking a specific question. So you found this lsd fiff in the car, then found the stub in the trunk, then ????/ please be more clear i am sorry i cannot tell you more yet. Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 I have read, and re-read, and reread again the first post for your question, and did not see that part..Actually the post more was like i found this, and now what? not asking a specific question. So you found this lsd fiff in the car, then found the stub in the trunk, then ????/ please be more clear i am sorry i cannot tell you more yet. woops. I was referring to the rest of the post I guess. which you didn't read I guess. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 Why does the ring clip stay in the diff in the pics in the link and in my pic it stayed on the stub? I dunno, that pic I posted was just an example, maybe when they went with the 'new' style axles (that dont' have the pin that goes in the stub) they changed to internal circlips? engineering choice I guess? Link to comment Share on other sites More sharing options...
bork Posted December 12, 2011 Share Posted December 12, 2011 look about halfway down here;http://www.iwsti.com/forums/how-install/116053-how-change-rear-axle.html thank you, Aren't all sub diffs this way? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 (edited) thank you, Aren't all sub diffs this way? someone may know for certain - but they may have switched from the style with the spring pin holding the axle on sometime around 2005(maybe started with the STI on 04 ?). I dunno about 'older generations'. The axles on the bottom of this pic seem to be 'new' style if you look at the far end - with the splines built on. The top ones are like my wife's 03 Outback. A spring pin holds them onto stub axles that stay inside the diff. I guess they've been built that way for decades. No fluid loss when changing axles. Dunno why they changed. Edited December 12, 2011 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 I think he meant aren't all soobies limited slip. No they are not. it was a very rare extra on old school cars. I don't know the new school stuff as well, but ther is plenty of info on the boards you can search LSD and VLSD Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 (edited) I think he meant aren't all soobies limited slip. No they are not. it was a very rare extra on old school cars. I don't know the new school stuff as well, but ther is plenty of info on the boards you can search LSD and VLSD duh - guess I got off topic! my wife's 03 OBW will definitely move rear wheels in the same direction if you spin one side. re there ways to tell from VIN numbers or markings on the diff if they are LSD? Edited December 12, 2011 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 12, 2011 Share Posted December 12, 2011 Why does the ring clip stay in the diff in the pics in the link and in my pic it stayed on the stub? To answer your question - they are different clip designs. The older style like your '91 VLSD stub axle used to be very common on almost every front wheel drive half-shaft (holds the axle into the transmission) but there have been problems with axle rebuilders and with installers not getting the clip centered or spreading the clip open too much prior to inserting it into the transmission/diff. Having the clip as a permanent part of the transmission or diff makes that problem go away and all axles fit easily and don't hang up on poorly installed clips. It just takes a lot of variability out of the equation by having the clip on the female side. It also can't get lost that way. Those pictures are of an STi axle - which fits only the R180 rear diff. They are not at all applicable to most Subaru's. Incidentally - VLSD's have a lifespan of about 50k miles. They lose most of their effectiveness as LSD's after approximately that long. Their sealed viscous disc pack is not serviceable or rebuildable like the clutch types and when they are worn out they are basically open diffs for the purposes of driving. Yes they will still lock enough to turn the wheels the same direction with a simple test of turning them by hand. But in actual driving they really don't do much unless they are new. Used - they are mostly just expensive open diffs that give people bragging rights but don't actually do much of anything useful. My '91 SS has it's factory VLSD still in place. At 176k on the body - I can't even tell it has an LSD. GD Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 Incidentally - VLSD's have a lifespan of about 50k miles. They lose most of their effectiveness as LSD's after approximately that long. Their sealed viscous disc pack is not serviceable or rebuildable like the clutch types and when they are worn out they are basically open diffs for the purposes of driving. Yes they will still lock enough to turn the wheels the same direction with a simple test of turning them by hand. But in actual driving they really don't do much unless they are new. Used - they are mostly just expensive open diffs that give people bragging rights but don't actually do much of anything useful. My '91 SS has it's factory VLSD still in place. At 176k on the body - I can't even tell it has an LSD. GD Well that sucks. I'll install it and see what it does on ice. Tex- all the ones I've seen have stickers that say VLSD or LSD for the clutch type. Like I said though, I am not familiar with the new school. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 12, 2011 Share Posted December 12, 2011 (edited) There are no stickers on the diffs past '94. You just have to know what models came with LSD's (Forester and Outback XT's, Most WRX's and all STi's of course, Some Legacy GT's.... etc). The only way to tell is to jack them up and turn the wheels. GD Edited December 12, 2011 by GeneralDisorder Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 To answer your question - they are different clip designs. The older style like your '91 VLSD stub axle used to be very common on almost every front wheel drive half-shaft (holds the axle into the transmission) but there have been problems with axle rebuilders and with installers not getting the clip centered or spreading the clip open too much prior to inserting it into the transmission/diff. Having the clip as a permanent part of the transmission or diff makes that problem go away and all axles fit easily and don't hang up on poorly installed clips. It just takes a lot of variability out of the equation by having the clip on the female side. It also can't get lost that way. Those pictures are of an STi axle - which fits only the R180 rear diff. They are not at all applicable to most Subaru's. Incidentally - VLSD's have a lifespan of about 50k miles. They lose most of their effectiveness as LSD's after approximately that long. Their sealed viscous disc pack is not serviceable or rebuildable like the clutch types and when they are worn out they are basically open diffs for the purposes of driving. Yes they will still lock enough to turn the wheels the same direction with a simple test of turning them by hand. But in actual driving they really don't do much unless they are new. Used - they are mostly just expensive open diffs that give people bragging rights but don't actually do much of anything useful. My '91 SS has it's factory VLSD still in place. At 176k on the body - I can't even tell it has an LSD. GD I was surprised my wife's outback behaved like it did, I'd expect a lot of slippage to be required to lock up a viscous pack. Seems backwards that is could work up on a jack, then fail if 'real' slippage occurs. Does the fluid degrade or what? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 There are no stickers on the diffs past '94. You just have to know what models came with LSD's (Forester and Outback XT's, Most WRX's and all STi's of course, Some Legacy GT's.... etc). They only way to tell is to jack them up and turn the wheels. GD yep, no shiny metal sticker on the diff. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 12, 2011 Share Posted December 12, 2011 I was surprised my wife's outback behaved like it did, I'd expect a lot of slippage to be required to lock up a viscous pack. Seems backwards that is could work up on a jack, then fail if 'real' slippage occurs. Does the fluid degrade or what? The fluid is in constant "sheer" by the plates. Every time the vehicle turns the wheels are forced to rotate at different speeds and that degrades and heat cycles the fluid inside. You have to understand the different forces involved between rotating the wheels by hand and them being driven by the car's engine and weight. You would need to rig up a torque wrench on one of the stubs to see what the break-away torque was, and then start spinning it faster to see what, if any, changes the heating of the fluid created in the amount of torque required to keep the discs in sheer. In practice no one ever does this and just assumes that LSD's and VLSD's work and last forever. Like all mechanical devices they do not. The clutch types can be rebuilt and also tuned by the amount of preload you put on the clutch pack. The VLSD's have no such ability. Once they start loosing their ability to lock-up they never get it back. GD Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 12, 2011 Share Posted December 12, 2011 The fluid is in constant "sheer" by the plates. Every time the vehicle turns the wheels are forced to rotate at different speeds and that degrades and heat cycles the fluid inside. You have to understand the different forces involved between rotating the wheels by hand and them being driven by the car's engine and weight. You would need to rig up a torque wrench on one of the stubs to see what the break-away torque was, and then start spinning it faster to see what, if any, changes the heating of the fluid created in the amount of torque required to keep the discs in sheer. In practice no one ever does this and just assumes that LSD's and VLSD's work and last forever. Like all mechanical devices they do not. The clutch types can be rebuilt and also tuned by the amount of preload you put on the clutch pack. The VLSD's have no such ability. Once they start loosing their ability to lock-up they never get it back. GD You'd think they would make that fluid replaceable. I could understand it being a 'throw-away' deal if the plates or something wore out or deformed, etc. But just for the lack of some fluid? weird. Link to comment Share on other sites More sharing options...
the sucker king Posted December 12, 2011 Author Share Posted December 12, 2011 SVX models had a viscous type too. don't think that was mentioned. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 12, 2011 Share Posted December 12, 2011 You'd think they would make that fluid replaceable. I could understand it being a 'throw-away' deal if the plates or something wore out or deformed, etc. But just for the lack of some fluid? weird. Yeah - the unit itself is tiny (like maybe 3" in diameter) and is all welded together with the fluid inside. Very similar to the 5MT center VC's. GD Link to comment Share on other sites More sharing options...
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